import java.util.Arrays;
import java.util.stream.IntStream;

public class O21 {
    public static void main(String[] args) {
        int x = 72; //scanf("&c",&c);
        char c = x>=90?'A':x>=80&&x<=89?'B':x>=70&&x<=79?'C':x>=60&&x<=69?'D':'E';
        System.out.println(c); //printf("%c",c)
    }
}
